1. Field of the Invention
This invention relates to a mechanism for guiding a head carriage of a rotary magnetic sheet device in an electronic still camera system or the like, and more particularly to an improvement which facilitates replacement of the head carriage and can position a magnetic head with high accuracy.
2. Description of the Prior Art
An electronic still camera system is the combination of an image pickup device using a solid-state imaging element or a camera tube and a magnetic sheet device which is a recording and reproducing device using a magnetic sheet as a recording medium. In such a camera system, still pictures of subjects electronically photographed are recorded on a magnetic sheet, and the picture information recorded on the magnetic sheet are reproduced by a television, a printer or the like. The magnetic sheet used in the rotary magnetic sheet device in such an electronic still camera system is accommodated rotatably in a casing and is thus available in the form of a magnetic sheet pack which is commonly called a video floppy.
This magnetic sheet has a diameter of about 50 mm, and about 52 tracks are provided in the radial direction at an interval of about 100 .mu.m. Because of such a high recording density, a magnetic head in the rotary magnetic sheet device must be positioned with very high accuracy in the radial direction of the magnetic sheet.
In view of such a severe requirement, a head carriage guiding mechanism as shown in FIG. 14 has been employed hitherto. In the prior art head carriage guiding mechanism shown in FIG. 14, a magnetic head 01 is carried by a carriage 02, and two guide shafts 03 and 04 slidably extending through the carriage 02 are fixed to a chassis 05. Therefore, by guiding the carriage 02 along the guide shafts 03 and 04, the magnetic head 01 is fed in the radial direction of a magnetic sheet.
In the prior art head carriage guiding mechanism shown in FIG. 14, the carriage 02 has a relatively large axial length at the portion where the guide shaft 04 extends therethrough. Because of the relatively large axial length of that portion of the carriage 02, not only the size and weight of the carriage 02 could not be reduced, but also a large burden has been imposed on a drive system driving the carriage 02. Further, since the guide shafts 03 and 04 are fixed to the chassis 05 through leaf springs fastened by screws, it has been inevitable that the magnetic head 01 tends to be dislocated depending on the magnitude of the tightening force imparted to the fastening screws. Also, the carriage 02 is to be replaced together with the magnetic head 01 due to excessive wear of the magnetic head 01, this replacement has been inconvenient in that the fastening screws must be loosened in order to take out the guide shafts 03 and 04.